import java.awt.*;
import java.awt.event.*;

public class SimpTree extends java.applet.Applet implements ActionListener
{
    TextField mQuery, mAnswer;
    Button bYes, bNo;

    public void init()
    {
        mQuery = new TextField(70);
        mQuery.setText("Do you have experience with formal notations?");
        bYes = new Button("Yes");
        bNo = new Button("No");
        mAnswer = new TextField(70);
        bYes.addActionListener(this);
        bNo.addActionListener(this);
        add(mQuery);
        add(bYes);
        add(bNo);
        add(mAnswer);
    }

    public void actionPerformed(ActionEvent event)
    {
        Object cause = event.getSource();
        if (cause == bYes)
        {
             mAnswer.setText(
              "In programming, you can see those notations come to life!");
        }
        else   // must have been the no button
        {
             mAnswer.setText(
              "Java is good because you will learn one notation very well.");
        }
    }
}